Okay, so today I took Bella to the vet for a general check up, her claws were clipped, her glands squeezed, a quick steroid injection to calm any itches then back home. Because we walked to the vets and back we didn't go for our normal walk.
She ate as normal, went out a few times as normal, a frequent visitor came round and she lay in front of the fire as normal. She finished off a large rawhide bone (larger than usual) and at about 11pm we went to bed (a bit later than usual) she went out before we went to bed..
Bella sleeps at the bottom of the bed and has access to the landing and stairs by the front door, the living room is closed off by a door. She has a water bowl by the bedroom door. Tonight she hasn't settled, she's drunk lots of water and peed at the bottom off the stairs
I can't understand it, she's only had one accident and that was on the first day she came to stay with me. I'm more inclined to believe it was the injection that has caused it as it's the only different thing I can think off. Can anyone confirm or suggest reasons?

She still won't settle now but she's lying next to me licking my arm.